^ I think in a real-life situation an Admiral wouldn't be "on the pulse" during such a command. Traditionally he'd be given his own command centre and would liase remotely with the main bridge, but to take the TMP situation as an example, Kirk would be in his quarters or an office on another deck or something, and not actually on the bridge (that'd be Decker's job). Of course this doesn't work dramatically, as we want to 'see' William Shatner in the big chair again, which is why the production team debated whether it'd just be easier to bump him to Commodore rather than Admiral, because it had been established in TOS that Commodores had that kind of authority.